It is based on kha vs rengar lore , alien vs predator .
When kha is lvl 16 and rengar gets 10 trophies on his neklerance a mission "the hunt is on" If kha kills or asist the kil he will get "the ultimate predator" + 4th evolve , if rengar do so he will get "head of kha'zix" and full stacks on his bonetooth neklerance.